VLA to EVLA Transition
The year 2010 was extremely exciting for the EVLA. The correlator that was the heart of the VLA for three decades was decommissioned on 11 January, 2010, and replaced with the new EVLA "WIDAR" correlator. The VLA was shut down to outside users until March 2010, during which time hardware was transferred from the old correlator to the EVLA correlator and observing modes commissioned in preparation for EVLA early science. At the same time the direction of the configuration cycles also changed, from A→B→C→D→A to D→C→B→A→D, in order to facilitate the EVLA correlator commissioning and to limit initial EVLA data rates. The last VLA antenna was retrofitted to EVLA specifications in May 2010.
During 2011 the WIDAR correlator was put into full observing mode with commissioning and Resident Shared Risk Observing starting in early 2011. By the end of 2011, up to 2 GHz of bandwidth was provided to the the general public along with 2 tunable bands, each with 8 spectral windows (64 to 256 channels) at S, Ku and X bands.
